Project description:BackgroundImplanting leadless pacemakers in the right ventricular (RV) apex is prone to causing pericardial tamponade and myocardial perforation.ObjectiveTo investigate the feasibility and safety of right ventriculography-guided implantation of Micra™ leadless pacemaker (Micra™, Medtronic, Minneapolis, MN, USA) in the RV mid-septum.MethodsOne hundred eight consecutive patients who underwent Micra™ implantation intended in the mid-septum were enrolled and randomized (3:1) into the radiography group (n = 81) with assistance of right ventriculography to illustrate the RV septum and the non-radiography group (n = 27). All subjects underwent a postoperative computed tomography (CT) scan to determine the Micra™ location. The Micra™ location assessed by CT image was compared between the two groups to confirm the accuracy of the intended pacing site. The duration of the procedure, X-ray radiation dose, and time were also compared between the two groups.ResultsReconstructed CT 3-D cardiac images found the Micra™ location in the intended mid-septum in 13 patients (48.1%, 13/27) in the non-radiography group and 76 patients (93.8%, 76/81) in the radiography group (P < 0.0001 between two groups). There was no significant difference in procedure interval between the two groups while the X-ray radiation dose (564.86 ± 112.44 vs. 825.85 ± 156.12 mGy, P < 0.0001), X-ray exposure time (7.79 ± 1.43 vs. 12.03 ± 2.86 min, P < 0.0001), and the number of fluoroscopy re-positioning (2.79 ± 1.03 vs. 6.41 ± 1.82, P < 0.0001) were significantly less in the radiography group than in the non-radiography group. No implantation-related complications were observed in both groups.ConclusionRight ventriculography increases the accuracy of Micra™ implantation in the mid-septum and reduces X-ray exposure.Trial registrationThe trial registration number (ChiCTR2100051374) and date (09/22/2021).
Project description:BackgroundThere is emerging evidence for the potential utility of left bundle branch area pacing (LBBAP), as an alternative to conventional cardiac resynchronization therapy (CRT). The utility of right ventriculography by way of power injector to facilitate lead placement has not yet been reported in the literature.Case summaryA 79-year-old female, with a background of poorly rate-controlled atrial fibrillation, presented with worsening dyspnoea. She had recently undergone single-chamber pacemaker insertion prior to an atrioventricular nodal (AVN) ablation, owing to failure in achieving successful CRT coronary sinus lead placement. She had clinical evidence of volume overload, and her electrocardiogram demonstrated right ventricular pacing. Echocardiography demonstrated left ventricular (LV) impairment, with an ejection fraction (EF) of 35%, and severe functional mitral regurgitation (MR). Her diagnosis was overall consistent with pacing-induced cardiomyopathy (PIC). In this patient, the use of right ventriculography, using power-injector-delivered contrast, successfully facilitated placement of an LBBAP lead, with confirmation of good threshold and sensing parameters. Following an upgrade to conduction system pacing, the patient recovered well. On recent follow-up, repeat echocardiography (24 months post initial presentation) demonstrated improved LV function (EF 45% from 35%) and only mild-to-moderate MR.DiscussionIn conclusion, we demonstrate the utility of right ventriculography to facilitate placement of an LBBAP lead, successfully treating a patient who developed PIC from chronic right ventricular pacing following AVN ablation.
Project description:Background Peripheral pulmonary nodules are often detected as multiple nodules in one patient. Computed tomography (CT) guided transthoracic biopsy (TTNB) is the most widely implemented method for minimal invasive biopsy of pulmonary nodules, but generally only one nodule is sampled per procedure. Navigation bronchoscopy is an endobronchial procedure with very low complication rates, and uses high-end image guidance which allows for the sampling of multiple nodules in one session, while also allowing inspection of the central airways and endobronchial ultrasound (EBUS) guided staging in one session. This report presents a unique case with three different synchronous primary tumors treated with three different treatment modalities that highlights the added value of cone-beam CT guided navigation bronchoscopy (CBCT-NB) in the diagnostic work-up of suspected early-stage lung cancer. Case Description This case describes an asymptomatic patient with no history of prior lung cancer referred because of a shadow seen on a screening X-ray. CT and positron emission tomography (PET) showed two nodules for which a navigation procedure was performed. Both nodules were sampled, and on inspection, a third occult endobronchial lesion was also found. Pathology revealed three separate primary tumors, which were treated with three different treatment modalities: surgery, radiotherapy and endobronchial cryoablation. Current follow-up at 12 months shows no signs of recurrence. Conclusions This case highlights that synchronous primary malignancies do occur and require a patient tailored approach to minimize treatment related morbidity and optimize survival. To this goal, image guided navigation bronchoscopy allows for a full and complete diagnostic evaluation and can be combined with a staging EBUS in one single session.
Project description:Diagnosis of acute myocardial infarction (AMI) is based on clinical symptoms of chest pain and dyspnea in combination with electrocardiographic changes and a raise in myocardial-specific biomarkers. Imaging is by echocardiography and magnetic resonance. The preferred technique for identification of previous myocardial infarction (MI) is magnetic resonance imaging with late gadolinium technique, but in the acute patient echocardiography is applied. In selected cases, important information can be obtained from other imaging modalities. We describe a case of a patient first suspected of an abdominal catastrophe in whom acute MI was diagnosed from a computerized tomography (CT) scan with iodine contrast. Our case together with a few other cases reported in the literature demonstrate that contrast enhancement of the myocardium can be important to follow in the acute patient because the CT scans sometimes give a unique opportunity to recognize findings consistent with MI even though the CT scan was performed for another reason.
Project description:How do we judge others' behavior when they are both seen and not seen-when we observe their behavior but not the underlying traits or history that moderate the perceived riskiness of their behavior? We investigate this question in the context of the COVID-19 pandemic: How people make sense of, and judge, vaccination-contingent behaviors-behaviors, such as going to the gym or a bar, which are considered to be more or less risky and appropriate, depending on the target's vaccination status. While decision theoretic models suggest that these judgments should depend on the probability that the target is vaccinated (e.g., the positivity of judgments should increase linearly with the probability of vaccination), in a large-scale pre-registered experiment (N = 936) we find that both riskiness and appropriateness judgments deviate substantially from such normative benchmarks. Specifically, when participants judge a stranger's behavior, without being asked to think about the stranger's vaccination status, they tend to judge these behaviors similarly positively to behaviors of others who are known to be fully vaccinated. By contrast, when participants are explicitly prompted to think about the vaccination status of others, they do so, leading them to view others more disparagingly, at times even more negatively than what a normative benchmark would imply. More broadly, these results suggest new directions for research on how people respond to risk and ambiguity. We demonstrate that even subtle cues can fundamentally alter what information is "top of mind," that is, what information is included or excluded when making judgments.Supplementary informationThe online version contains supplementary material available at 10.1007/s11166-022-09396-7.
Project description:Hollow hard shell particles of 200 nm and 2 micron diameter with a 10 nm thick porous silica shell have been synthesized using polystyrene templates and a sol-gel process. The template ensures than the hollow particles are monodispersed, while the charged silica surface ensures that they remain suspended in solution for weeks. When filled with perfluorocarbon gas, the particles behave as an efficient contrast agent for colour Doppler ultrasound imaging in human breast tissue. The silica shell provides unique properties compared to conventional soft shell particles employed as ultrasound contrast agents: uniform size control, strong adsorption to tissue and cells immobilizing particles at the tissue injection site, a long imaging lifetime, and a silica surface that can be easily modified with biotargeting ligands or small molecules to adjust the surface charge and polarity.
Project description:Thermoelectric properties of semiconductors are intimately related to their electronic band structure, which can be engineered via chemical doping. Dopant Ga in the cage-structured skutterudite Co4Sb12 substitutes Sb sites while occupying the void sites. Combining quantitative scanning transmission electron microscopy and first-principles calculations, we show that Ga dual-site occupancy breaks the symmetry of the Sb-Sb network, splits the deep triply-degenerate conduction bands, and drives them downward to the band edge. The charge-compensating nature of the dual occupancy Ga increases overall filling fraction limit. By imparting this unique band structure feature, and judiciously doping the materials by increasing the Yb content, we promote the Fermi level to a point where carriers are in energetic proximity to these features. Increased participation of these heavier bands in electronic transport leads to increased thermopower and effective mass. Further, the localized distortion from Ga/Sb substitution enhances the phonon scattering to reduce the thermal conductivity effectively.
Project description:The crystal structure of EuRu(4)P(12) is isotypic with filled skutterudite structures of rare earth transition metal poly-phosphides: RFe(4)P(12) (R = Ce, Pr, Nd, Sm and Eu), RRu(4)P(12) (R = La, Ce, Pr and Nd) and ROs(4)P(12) (R = La, Ce, Pr and Nd). The Ru cation is coordinated by six P anions in a distorted octa-hedral manner. The partially occupied Eu position (site occupancy 0.97) is enclosed by a cage formed by the corner-shared framework of the eight RuP(6) octa-hedra.